Recently, people started reporting that bibliographic data (e.g. citation information) is missing from the OPS family request.
David Reymond of Patent2Net fame  already reported this issue and it also had an impact on PatZilla  as well.
 GitHub - Patent2net/P2N-v3: Last version workong on...
 GitHub - ip-tools/ip-navigator: A modular patent information research platform and data integration toolkit with a modern user interface and access to multiple data sources.